An instrument panel is provided at a front side inside a cabin (vehicle chamber) of a vehicle in a vehicle width direction. An air conditioning unit and the like is embedded in the instrument panel. The air conditioning unit is a cooling cycle equipment including a compression device, an evaporator, a condenser, an air conditioning piping, a blower, and the like. The air conditioning piping connects the compression device, the evaporator, and the condenser. The air conditioning piping and the like are placed between an engine room and the cabin. Therefore, a penetration hole is formed on a dashboard lower section (a dashboard lower panel) dividing the engine room and the cabin. The air conditioning piping passes through the penetration hole.
Here, an air conditioning boot (a seal boot) is provided on the dashboard lower section. The air conditioning boot prevents rain and dust from entering the cabin side from the penetration hole. The air conditioning boot includes a boot part and an annular fitting groove. The boot part is approximately cylindrically shaped. The boot part is formed so as to surround a peripheral of the penetration hole. The annular fitting groove is provided at an end of the boot part and is fitted and fixed to an interior of the penetration hole. Furthermore, the air conditioning piping is arranged inside the air conditioning boot. (See, for example, Japanese Unexamined Patent Application, First Publication No. 2004-114922.)
Incidentally, when the air conditioning boot is provided on the dashboard lower section, the vibration of the engine and noise from the roads will be transmitted to the dashboard lower section via the air conditioning boot. The dashboard lower section merely separates the engine room from the cabin. Therefore, the dashboard lower section is often formed with a thin plate in order to reduce the weight of the dashboard lower section. As a result, there is a problem in that the dashboard lower section undergoes a membrane vibration. There is also a problem in that an NV characteristic of the air conditioning wiring declines.
The present invention is made according to the considerations described above. The present invention provides a frontal structure of a vehicle which prevents the dashboard lower section from undergoing a membrane vibration, and also enhances an NV characteristic of the air conditioning wiring.
In addition, generally speaking, a damping material (a sound insulator) is attached to a dashboard lower section (a dashboard lower panel) separating an engine room from a cabin (a vehicle chamber). The damping material reduces the influence of noise inside the engine room and vibration to the cabin chamber. A so-called melting sheet is used as the damping material, for example. The melting sheet, such as an asphalt sheet and the like, has viscosity and elasticity. (See, for example, Japanese Unexamined Patent Application, First Publication No. H7-309253.)
For instance, the damping material may be fixed by using a plate that presses the damping material. The damping material is sandwiched between the plate and the dashboard lower section. Under this condition, the plate is fixed to the dashboard lower section by spot-welding.
By the way, according to the conventional technology described above, it is necessary to thicken the damping material and the plate material in order to prevent the dashboard lower section, the damping material, and the plate pressing the damping material from undergoing a membrane vibration. As a result, the cost of the materials used to manufacture the damping material and the plate pressing the damping material increases. At the same time, there is also a problem in that the weight increases.
The present invention is made according to the considerations described above. The present invention provides a frontal structure of a vehicle which can reduce the cost of materials and the weight.
In addition, generally speaking, a damping material (a sound insulator) is attached to a dashboard lower section (a dashboard lower panel) separating an engine room from a cabin (a vehicle chamber). The damping material reduces the influence of noise inside the engine room and vibration to the cabin chamber. A so-called melting sheet is used as the damping material, for example. The melting sheet, such as an asphalt sheet and the like, has viscosity and elasticity. A reinforcing plate is provided to attach the damping material to the dashboard lower section. The damping material is sandwiched between the reinforcing plate and the dashboard lower section. Under this condition, the reinforcing plate is fixed to the dashboard lower section by spot-welding.
Here, when the damping material is attached to the dashboard lower section, a gravitational force applies to the damping material. As a result, the damping material may decline. Accordingly, various technology is suggested to prevent the damping material from slipping.
For example, an elevated portion is formed at an appropriate place of the reinforcing plate at which an attachment is made to the dashboard lower section. The elevated portion is formed by making the reinforcing plate concaved towards the dashboard lower section side. The elevated portion bulges towards an interior of a closed cross section. An opening hole is provided at a peak part of the elevated portion. A flange part is formed in the periphery of the elevated portion. The tip end of the flange part approaches the dashboard lower section. In this way, a locating portion of the damping material is formed. (See, for example, Japanese Unexamined Patent Application, First Publication No. H7-309253.) According to this technology, the damping material latches with the elevated portion, which forms the locating portion. The damping material also latches with the flange part around the rim of the opening hole. As a result, the damping material is prevented from dislocating.
However, according to the conventional technology described above, the opening hole is provided merely to prevent the damping material from dislocating. Therefore, when the reinforcing plate is fixed to the dashboard lower section so as to sandwich the damping material in between, it is difficult to determine from the outside whether or not the damping material exists. As a result, there is a problem in that one may forget to place the damping material. There is also a problem in that the operation of determining whether or not the damping material has slipped becomes burdensome.
The present invention is made according to the considerations described above. The present invention provides a frontal structure of a vehicle which prevents the damping material from being forgotten to be attached. The present invention also provides a frontal structure of a vehicle which allows one to easily determine whether or not the damping material has slipped.